In the process of drilling wells, wellbore fluids or drilling muds are pumped downhole from the well drilling platform. Often these drilling fluids lubricate the drill bit and carry away cuttings generated as the drill bit digs. The cuttings and other solids are carried in a return flow stream with the fluids up to the well drilling platform at the surface. The solids are typically small pieces of shale or rock. Once the drilling fluids and solids reach the platform, a “shale shaker” located on the platform is typically used to remove the solids from the drilling fluids so that the fluids may be reused.
But it is not always possible to separate all the solids from the drilling fluids with a shale shaker. Many times the solids are simply too small to be separated with a shaker. Generally, the shale shakers are only able to separate 60-70% of contaminant solids from drilling fluids. Additionally, drilling fluids are frequently formulated to contain finely ground solid additives that a shaker cannot distinguish from fine drilling solids, known as low gravity solids. Barite, a well know weighting agent, is one example of such solid additives. When shakers alone are insufficient, additional drilling waste management equipment is often used to further separate the solids from the drilling fluid. Drilling waste management equipment generally refers to the pumps, tanks, and centrifuges that are capable of separating the fine drilling solids from the drilling fluid. Without this additional treatment, the solids-contaminated drilling fluid cannot be re-used and must be discarded.
Drilling waste management systems incorporating the waste management equipment are effective for separating the fine solids from the drilling fluid and returning the fluid to the drilling rig. Unfortunately, existing drilling waste management systems are complicated and expensive to install at the rig site. These systems arrive in pieces that must be shipped to the rig site in multiple truckloads. A crane and its crew are necessary to lift the pieces from the truck trailer and place them at the rig site. Once the pieces are in place, the components of the drilling waste management system must be interconnected by skilled personnel. When the drilling operation is complete, the system must then be disassembled with a crane and shipped offsite in multiple truckloads. The shipping costs, crane rental costs, and labor costs associated with these operations are significant.
In addition to the expenses related to existing drilling waste management systems, the space requirements of these systems are another drawback. Existing systems need a relatively large amount of space at the rig site. The equipment itself has a significant footprint. Also, the cranes and trucks involved in shipping and assembly need additional space to maneuver. This is a significant drawback because drilling rig sites are becoming smaller and space is at a premium.
The safety of existing drilling waste management systems is also a concern. There is inherent danger associated with operating cranes, lifting heavy equipment, maneuvering trucks, and installation labor, e.g. welding. The assembly required by existing drilling waste management systems increases the likelihood that accidents may occur.
Consequently, there is a need for an improved drilling waste management system that reduces and/or eliminates the need for multiple delivery truckloads of equipment, crane operations, and assembly labor. There is also a need for a drilling waste management system that minimizes the drilling rig space necessary to setup and operate the system.